For visual and audio reception/reproduction systems (AV (Audio Visual) systems), many types of thin liquid crystal display devices have recently been developed as a monitor section (AV output device) that reproduces (displays) images. A liquid crystal display device is greatly advantageous in that a display screen can be enlarged while the display device remains light and thin.
Utilizing this advantage, there is such a system disclosed that a tuner section of a television receiver is separated from a monitor section of the television receiver, and an image signal and an audio signal are supplied from the tuner section to the monitor section. In this system, the tuner section thus separated is provided with an antenna wire to allow for channel selection, and images based on an AV signal are reproduced by wirelessly supplying the image and audio signals (AV signal) of the selected channel to the monitor section (e.g. Patent Documents 1 and 2).
Patent Document 1 is Japanese Laid-Open Patent Application No. 2001-160927 (published on Jun. 12, 2001).
Patent Document 2 is Japanese Laid-Open Patent Application No. 2001-358966 (published on Dec. 26, 2001).
According to the aforesaid system, in response to an operation such as channel selection and input switching on the monitor side, a command corresponding to the operation is generated on the monitor side and supplied to the tuner side. This command prompts the execution of a process on the tuner side, and is transmittable on a wireless transmission system associating the monitor side with the tuner side. The monitor side in this case transmits the command at an interval specified by the wireless transmission system.
Meanwhile, on the tuner side, the channel selection, input switching, or the like is performed in response to the command. Subsequently, on the tuner side, an image signal having been subjected to the channel selection or input switching is converted to stream information. This stream information is wirelessly transmitted to the monitor side. The conversion to the stream information is, for instance, MPEG (Moving Picture Expert Group) 2 conversion. Since this MPEG2 conversion takes some time, undesirable visual disturbance occurs for several seconds on the screen on the monitor side, during a period in which a process concerning the channel selection or input switching is performed on the tuner side. To avoid this problem, for instance, image display on the screen is stopped for not less than several seconds. Note that, hereinafter, stopping the image display is referred to as “to mute”.
When the MPEG2 conversion is performed in this manner, a delay time related to switching, e.g. a delay time concerning encoding, is relatively long, and hence a period of visual disturbance on the monitor side is also relatively long.
In addition to the above, it is impossible on the monitor side to recognize when an image signal to be supplied is switched, after a demand of channel selection or input switching is, by means of a command, sent to the tuner side. On this account, the management of a mute period is performed based on a time at which the demand is made. Also, to hide the visual disturbance by means of the muting, when the visual disturbance disappears is estimated and the muting is terminated after that estimated time. In this manner, there has been such a problem in the conventional art that the mute period must be longer than an actual period of visual disturbance.
The present invention was done to solve the above-identified problem, and the objective of the present invention is to provide, for instance, an image display system that allows the mute period to approximate to the actual period of visual disturbance.
Another objective of the present invention is to provide a technology that makes it possible to grasp an image mute timing on the display device side and to properly perform the time setting.